/**
 * Created by Sixgod on 2016/4/20.
 */
var mergeCanvas = function(url){
    return 'var c = document.getElementById("result");' +
        'var cxt = c.getContext("2d");' +
        'var img = new Image();' +
        'img.src = url;cxt.drawImage(img,0,0);';
};